Manual says it's holding R1 then quickly tapping R2 with left stick pressed towards the ball. Computer does it all the time: flick the ball ahead and run past. I am sure CPU-Walcott has no trouble skinning human-controlled Terry. But the CPU-players are so clairvoyant, they recognize your move and change direction or stick their foot out like a switch blade instantaneously while you are still caught in your animation cycle.

Holding Super-Cancel and leaning into the other player with the left stick sometimes seams to help to counter the stumbling thingy.